Catalytic conversion and catalysts



United States Patent Indiana No Drawing. Filed Mar. 28, 1956, Ser. No. 574,363 17 Claims. (Cl. 260-943) This invention relates to novel polymerization catalysts and polymerization processes. The present invention provides processes suitable for the polymerization of compounds containing ethylenic unsaturation. it is especially suitable for the homoor heteropolymerization of hydrocarbons containing ethylenic unsaturation, particularly vinyl monolefinic hydrocarbons. By the process of the present invention, unbranched, normally gaseous l-alkenes can be polymerized to yield normally solid materials of high molecular weight, especially highly crystalline, resinous materials.

One object of my invention is to provide novel catalysts for the polymerization of organic compounds containing ethylenic unsaturation. More specific objects are to provide novel catalysts and processes for the polymerization of vinyl monolefinic hydrocarbons. An additional object is to provide novel catalysts and processes for the polymerization of unbranched, normally gaseous 1- alkenes to produce relatively dense, resinous polymers. Yet another object is to provide new catalysts and processes for the polymerization of ethylene and/or other normally gaseous, unbranched l-alkenes to produce solid polymers having high molecular Weights and high degrees of crystallinity. A further object is to provide processes for the production of isotactic polymers from propylene, l-butene, styrene and other monomers which ofier the possibility of yielding isotactic polymers (note G. Natta, l. Polymer Sci. 25, 143454 (April 1955)).

In accordance with my invention, organic compounds containing ethylenic unsaturation are polymerized readily under relatively mild reaction conditions with catalysts (hereinafter speciied) and catalyst promoters to produce addition polymers, and in many cases, normally soli polymers. As catalyst promoters, I use small proportions, based on the weight of the catalyst, of organic eroxides, i.e., compounds having the general formula ROOR wherein R is an organic radical and R is selected from the group consisting of hydrogen and organic radicals. -When R is a hydrocarbon radical and R is hydrogen or a hydrocarbon radical, the peroxide may be referred to as a hydrocarbon hydroperoxide.

The catalysts employed in the polymerization process are prepared by mixing a salt of a transition metal selected from Groups 4, 5, 6 or 8 of the Mendelefr" ieriodic Table with an alkali reagent selected from the group consisting of the alkali metals or their hydrides or hydrocarbon derivatives, or a mixture of two or more of the aforesaid alkali reagents. The admixture can be effected in an inert liquid reaction medium such as a saturated hydrocarbon. The admixture of the metal salt and alkali reagent appears to result in partial reduction of the positive valence state of the metal contained in said salt; more or less highly colored complexes form between the partially reduced salts and alkali reagents and/or other interaction products.

The molar ratios of polyvalent metal salt and alkali reagent can generally be varied broadly over the range of about 0.1 to about 10, more or less. It is preferred to use a molar excess of reducing agent (the alkali reagent) with respect to the polyvalent metal salt. In some cases the interaction proceeds at an appreciable or even high rate at room temperature; however, the

3,157,627. Patented Nov. 17, 1964 "ice temperature can be varied, depending on the specific re actants, between about 20 C. and about 300 C. The admixture can be eiiected in the presence or absence of the monomer or mixture of monomers which is to be polymerized. The partially reduced catalytic mixture can be stabilized by adding small proportions of a highly reactive olefin thereto, e.g. styrene, indene or the like.

I have found that the polymerization activity of the catalyst prepared by reaction of alkali reagents with the specified metal salts can be substantially increased (as evidenced by increased yields of polymer under otherwise comparable conditions) by the inclusion of an organic peroxide in the reaction zone. The proportion of organic peroxide which is employed can vary from about 0.01 to about 20% by Weight, based onthe weight of the alkali reagent which is employed in the preparation of the catalyst, but usually Within the range of about 1 to about 10 weight percent, preferably about 3 to about 6 weight percent. The peroxide promoter can be introduced in one or a plurality of charges, intermittently or continuously, in the step of catalyst preparation; with the polymerization feed stock or as a separate charge to the reaction zone before or during polymerization.

i-olymerization can be eiiected at selected temperatures which vary in accordance with the polymerization activity of the specific monomer(s), catalysts, promoter, desired reaction rate and the type of product which is desired. The selected polymerization temperatures generally fall within the range of about 40 C. to about 300 C., more often about 0 C. to about 250 0; say about 10 C. to 175 C. for ethylene and similar monomers.

The preparation of catalysts and the polymerization are preferably effected in the absence of impurities which react with and consume the catalysts or the components of the catalytic mixture, such impurities being oxygen, carbon dioxide, water, etc.

Polymerization can be effected at atmospheric pressure or even lower pressures, but it may be advantageous to use superatmospheric pressures in order to obtain desirable monomer concentrations in contact with the catalyst. Thus, the polymerization can be conducted at pressures up to 10,000 p.s.i. or even higher pressures. Usually polymerization is effected at pressures between about 50 and about 2000 p.s.i.a.

The weight ratio of catalyst mixture to monomer can generally be varied in the range of about 0.01 to about 10% by weight, for example, about 0.1 to about 5 weight percent; even weight percent catalyst can be used in flow operations.

Polymerization can be effected by contacting the unsaturated feed stock at the selected temperature and pressure with the mixture produced by the interaction of the catalyst components or with individual components of said mixture which exhibit catalytic activity.

Polymerization is preferably performed in the presence of various reaction media which remain liquid under the selected polymerization conditions of temperature and pressure. I prefer to employ relatively inert liquid reaction media such as saturated hydrocarbons, aromatic hydrocarbons, relatively unreactive alkenes, or cycloalkenes, perfluorocarbons, chloroarornatics or mix tures of suitable liquids.

Suitable agitation of the catalyst and monomer(s) is provided to secure efiective contacting by means which are well known. Removal of the heat generated in polymerization can be effected by known means.

Through the present process, I can convert ethylene to wax-like homopolymers having an approximate specific viscosity (X10 between about 1000 and 10,000 and tough, resinous ethylene homopolymers having an approximate specific viscosity 10 of 10,000 to more enema? 3 than 300,000. Propylene can be polymerized by the presout process to normally solid materials which soften at temperatures well above room temperature, for example, at least about 75 C. or even much higher temperatures (in some cases exceeding the melting points of high molecular weight, solid polyethylenes). V

The following examples are provided to illustrate the invention but not unduly to limit its broad scope.

The examples hereinafter tabulated were performed in glass reactors (100 cc. volume) employing 40 cc. of dry, distilled n-heptane as the liquid reaction medium. Polymerization operations were initiated at room temperature, after adding the catalyst and promoter components to the heptane, by introducing ethylene at 50 p.s.i.g. and allowing the reaction mixture to warm up. due to the exothermic reaction. The reaction period was, in each instance, 20 hours. The Staudinger specific viscosities were determined upon solutions of 0.125 g. of polymer in 100 ml. xylenes at 119 C. The melt viscosities at 145 C; were determined by the method of Dienes and Klemm, J. Appl. hhys. 17, 458-71 (1946). Densities were determined at 24 (1. Unless otherwise indicated, the reaction mixture was worked up as follows. The reaction mixture was treated with dilute hydrochloric acid and then washed with water while agitating. The polymer was filtered and washed with Water, then with acetone, dissolved in hot xylenes, filtered to remove intemperature and diluted with acetone to precipitate the solid polymer. It will be noted that the peroxides in each instance exerted substantial promotional effect in increasing the yields of solid polymer of high molecular weight. 7

V mers, especially vinyl monoolefinic hydrocarbons such as.

ethylene, propylene, styrene and the like, employing de- 7 organic materials and the filtrate was then cooledtoroom ene, l-butene, l-pentene, l-hexene and mixtures of one or more of these alkenes, or the like.

The process of the present invention can also be applied sired proportions of each monomer in a composite feed stock. 7

Vinyl arenes are suitable feed stocks, used alone or as comonomers with vinyl alkenes or conjugated alkadienes. 7

Examples of vinyl arenes are styrene, nuclearly alkylated (especially methylated) styrenes, nuclearly halogenated styrenes and the like.

The invention can also be applied to such highly reactive olei'ins as indene and the like. The invention may be applied to Z-butene, Z-pentene, isobutylene, Z-methyl '2-butene, nethyl-l-hexene, tetrafluoroethylene, trifluorochloroethylene, t-butylethylene and the like, these olefins being employed as the sole feed stock or in minor proportions based upon some other monomer such as ethylstock. Our invention is especially useful and yields unexpected results when the monomer is a normally gaseous,

unbranched l-alkene, especially ethylene and/or propyl- Table I Alkali Yield of a Run Reagent G. Peroxide G. Salt G. Polrmer, Properties of Polymer None T1014- 1. 09 1. 1 d=0.9443; M.V.=1.0 Di-t-butyl peroxide TiOh--. 0. 43 1.8 do T1014- 1 09 4. 2 d=0.9667;1\ .V.=1.l 10

2,2-bis(tert-butyl-paroxy)butane TiCl4 1. O9 6. 3 d=O.9367; M.V.= l.1 (10 Benzoyl peroxide 0. 27 'IiCln 1.09 2.8 d= 1.0342; M.V. =7.0 10

1 Reaction initiated at 0.

My invention can be substantially extended from the specific illustrations thereof which have been supplied. Thus, the novel catalysts can be applied to the treatment of any organic compound containing an ethylenic linkage Which is susceptible of addition polymerization, for example, the well known vinyl monomers, which need not be specified in detail herein (cf. C .E. Schildkneeht, Vinyl and Related Polymersjf Sohn Wiley 8: Sons, N.Y. (1952) A particularly important application of the catalysts of the present invention is for the polymerization of vinyl monoolefinic hydrocarbons, the term vinyl being defined as CH2:CH (CA. 39, 5965 (1945)). The vinyl monoolefinic hydrocarbons have the general formula any of the alkali metals or alloys, or mixtures of alkali metals, or hydrides or hydrocarbon derivatives of alkali metals can be employed. Suitable alkali metal alloys informula MR, wherein R represents a monovalent hydrocarbon radical which maybe saturated or unsaturated, for

example, an alkyl, aryl, aralkyh alkaryl, cycloalkyl, conjugated cyclodienyl, and other hydrocarbon radicals.

wherein R is" selected 'from'the group consisting of hydrou'herein R is hydrogenor an alkyl radical. Specifically, suitable vinyl alkene feed stocks comprise ethylene, propylbe' prepared by conventional techniques in situ,*e.g., by t the reaction of an alkali metal with a highly, reactive metal .alkyl suchas a dialkyl mercury, adialkyl zinc or the like; 5'

by the reaction of alkyl or allylic halides with alkali metal,

Suitable alkyl radicals include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, 'octyl, dodecyl, hexadecyl, oct'adecyl, eicosyl, and the like, for example, as in ethyl sodium, methyl lithium, butyl lithium, methyl sodium, 5

octyl potassium. Other suitable alkali metal compounds include 'isopropyl potassium, benzyl sodium, sodium acetylides, allyl sodium, etc. Org'ano-aLrali compoundsican etc. '1

j Salts of the following metalslcan be used in the prepara- 1 7 tion of polymerization catalysts for the purposes of my invention: Ti, Zr; Hf, Th, V, Nb, Ta, U, 'Cr, Mo, W,Mn,

In the preparation of suitable polymerization catalysts,

.Fe, Co, Ni, Ru, Rh, Pd, Os, 'Ir, Pt or mixtures of salts;' of said metals. Theseare the transition metals of Groups 4a, 5a, 6a, and 8 of the Mendelefi Periodic Table (Kirk- Othmer, Encyclopedia of Chemical Technology, vol. 5, pages 669672 (Interscience, New York, 1950)). I can employ the metal salts of various mineral acids, for example, the hydrohalogen acids; oxyhalides, e.g., titanyl chloride or vanadyl chloride and the like; salts of acids of phosphorus, sulfur, n trogen, etc. I may also use the specified metal cyanides, cyanates, isocyanates, thiocyanates, isothiocyanates, azides, etc. The salts of carboxylic or sulfonic acids may also be used. Also I may use metal derivatives, classified herein as salts, having the formula M(OR),,, wherein M represents the polyvalent metal, R is an alkyl or aryl radical, and n is the valence of M, for example, T i(OC 'H Ti(OC H tetra-Z-ethylhexyl titanate, tetrastearyl titanate, tetraphenyl zirconate and the like, for example, the metal derivatives of the enol forms of acetylacetone, acetoacetic ester and the like.

In addition to or in lieu of the aforesaid metal salts, I may employ freshly precipitated oxides of hydroxides of said metals, which can be prepared by techniques which are well known in inorganic chemistry.

It will be understood that the various alkali reagents do not yield precisely the same results and the same is true of the various metal salts which may be employed to prepare catalysts for use in my invention. The broad variety of reagents which can be used to prepare active polymerization catalysts affords great flexibility in my invention.

The preparation of the catalyst can be effected in the presence of various solid materials, such as carbon, silica,

lumina, bauxite, iluorided alumina, synthetic or natural aluminosilicates, magnesia, titania, zirconia, powdered aluminum fluoride, sodium fluoride, sodium chloride, cryolite or the like. The added solid material can comprise from about 10 to 2060 weight percent, based on the weight of the materials which are allowed to react to form the polymerization catalysts.

In some cases, maximum catalytic activity can be attained by depositing or sorbing the polyvalent metal salt on the surface or" a solid material, egg. by stirring a solution or dispersion of said polyvalent metal salt with the finely-divided solid support, thereafter adding the alkali reagent to effect partial reduction of said salt and the formation of an extended, supported catalyst.

A wide variety of organic peroxides may be employed as catalyst promoters for the purposes of the present invention.

The organic peroxides which can be employed include the organic hydroperoxides, having the formula ROSE-1, wherein R is an organic radical, usually a hydrocarbon radical such as a saturatedhydrocarbon radical or an alkenyl or cycloalkenyl radical. Gther peroxides which can be used have the structure R001 wherein R and R re organic radicals, for example, hydrocarbon radicals such as alkyl, aryl, aralkyl,-cycloalkyl, etc. In addition, I can employ peroxycarboxylic acids of either the aliphatic or aromatic series, having the general formula 0 Riloor-r wherein R is an organic radical, usually a hydrocarbon radical. I can also employ esters or salts of the org i peroxy acids. Other peroxides which can be employed include diacyl and diaroyl peroxides and various peroxy derivatives of aldehydes and ketones such as l-hydroxyalkyl hydroperoxides, l-hydroxycycloalkyl hydroperoxides, and the like.

The saturated aliphatic hydroperoxides include the hydroperoxides of primary, secondary and tertiary saturated monovalent hydrocarbon radicals, for example, methyl hydroperoxide, ethyl hydroperoxide, t-butyl hydroperoxide, l-methylcyclopentyl hydroperoxides, l-ethylcyclohexane hydroperoxide, l-methylcyclohexane hydroperoxide, and the like.

6 I can also use hydroperoxides of olefins such as the pentenes, hexenes, Z-methyl-Z-butene, cyclohexene, cyclopentene, l-methylcyclohexene, 3-p-menthene, methyl oleate or other alkyl oleates, polyolefins containing l,4-unsaturation, polyolefins containing 1,5-unsaturation, or their mixtures, or the like.

I can employ aralkyl hydroper'oxides', particularly those having the general structure R1 Ar0 OH wherein Ar represents an aromatic monovalent radical, usually a hydrocarbon radical; R and R are the same or different alkyl radicals or are united, together with the alpha carbon atom, to form a polyrnethylene radical such as cyclopentyl, cyclohexyl, or the like. Examples of such peroxides are cumene hydroperoxide and the hydroperoxides obtained from sec-butylbenzene, p-cymene, 0- or p-diisopropylbenzene (monoor di-hydroperoxides), cyclohexylbenzene and cyclopentylbenzene. Other aralkyl hydroperoxides include tetralin hydroperoxide and hydroperoxides obtained from p-xylene or ethylbenzene (H. Hock et al., Ber. 76, 169 (1943)), diphenylmethane, 1,4- dihydronaphthalene, l-methyl tetralin, etc.

The hydroperoxides need not be used in pure condition. The can readily be prepared by known methods of oxidizing alkyl aromatic hydrocarbons with oxygen or air. The resulting reaction mixture can be used as part or all of the liquid reaction medium for polymerization in the process of the present invention.

1 can employ symmetrical or unsymmetrical dialkyl peroxides such as dimethyl peroxide, methyl ethyl peroxide, diethyl peroxide, di-t-butyl peroxide, didodecyl peroxide, diisopropyl peroxide and the like. Di-t-butyl peroxide and 2,2-bis(tert-butyl-peroxy)butane are preferred because of relative safety and ease of handling.

1 may also use polyperoxides derived from vinyl monomers such as styrene, vinyl acetate, methyl methacrylate, etc.

I may also employ transannular peroxides, for example, ascaridole.

I may employ a wide variety of organic peroxy acids, i.e. peroxycarboxylic acids, for example, peracetic acid, peroxybenzoic acid, peroxytrichloroacetic acid, peroxytrifluoroacetic acid, monoperoxyphthalic acid, diperoxyphthalic acid or the like. (Note, for example, D. Swern, Chem. Reviews, 45, 1 (1949)).

A wide variety of diacyl and diaroyl peroxides can be employed for the purposes of our invention, for example, benzoyl peroxide, diacetyl peroxide, 'di-n-butyryl peroxide and the like. We can also employ various dialkyl peroxydicarbonates, for example, methyl, ethyl, propyl, n-butyl, isopropyl, t-butyl or other dialkyl peroxydicarbonates which can be prepared by known methods (note F. Strain et al., 3. Am. Chem. Soc. 72, 1254 (1950)).

I may also employ peroxy derivatives of aldehydes and ketones such as the l-hydroxyalkyl hydroperoxides, alkyl l-hydroxyalkyl peroxides, bis(1-hydroxyall yl) peroxides, polyalkylidene peroxides, peroxyacetals and the like.

. Specific examples of peroxy derivatives of aldehydes and ketones which can be employed include l-hydroxycyclohexyl hydroperoxide, bis(l-hydroxycyclohexyl). peroxide, trimeric cyclohexanone peroxide, bis(hydroxymethyl) peroxide, trimeric acetone peroxide, dimeric acetone peroxide, dirneric benzaldehyde peroxide, etc.

The polymeric products produced by the processes encompassed within the scope of our" invention can be subjected toa variety of treatments designed to remove all or part of the catalytic materials therefrom. Thus the polymers can be washed with methanol, alcoholic alkalies, or

the like in order to convert halide salts to the corresponding metal hydroxides. a

The solid polymeric products can be dissolved in hot solvents, for example in unreactive hydrocarbons such as 7 3 r saturated or aromatic hydrocarbons, and the resultant and about 175 C. and a pressure below 2000 p.s.i.a., with solutions can be treated to separate polymer having relaa polymerization catalyst prepared by admixing tively low content of material derived from the catalyst (A) an alkali reagent selected from the class consistcomponents. Thus hot hydrocarbon solutions of polymer ing of: t can be subjected to the action of various hydrolytic agents (l) alkali meta to precipitate metal hydroxides which can then be sepa- (2) alkalimetal hydride t rated from the remaining solution by centrifuging, de (3) hydrocarbon derivative of an alkali metal, and cantation, filtration or other 'means. Alternatively, the (4) mixtures of said alkali reagents, with hot hydrocarbon solution of, polymer can be cooled or (B) a pclyvalent metal salt of a metal selected from treated with precipitants or antisolvents such as acetone, V the Groups 421, 5a, 6a and 8 of the Mendeleflf-Periodmethanol or the like to precipitate a small proportion, ic Table, the improvement of ejecting said contactsay up to about 5 weight percent of the solute polymer, ing in the presence'of a diacyl peroxide in a proporwhich precipitate contains a very large proportion of the tion sufficient to effect substantial promotion of the inorganic materials originally present in the polymer. 7 activity of said polymerization catalyst of from The solvent can be recovered from the aforesaid oper- 5 about 0.01 to about percent by weight of said. ations and can be reused. alkali reagent and recovering a polymer thus pro- A desirable method for Working up normally solid duced, t polymers or ethylene is to, prepare a hot solution thereof 7. The process of claim 6 wherein said diacyl peroxide in a normally liquid alkane, particularly in the C C i benzoyl peroxide. range, having a SQlllifi cfiflcenimtion'oftho Order Of 20 8. In a process for the conversion of an unbranched, weight percent, thereafter to filter said solution ,(optionll gaseous L u a normauy lid l V with a l thmugll a Conventional filler 1119- which is process comprises contacting a feed stock condlum remove Suspended Particles dew/3d from the taining said alkene at atemperature between about 10 C. polymerization catalyst (optionally) to contact the filtrate d b ut 175 C, with a polymerization catalyst prowith an adsorbent filter aid in order to effect selective d b i j lkali metal with a, halide of a metal adsorption of colloidal P y Particles from The hot of Group 4a of the'Mendeleif Periodic Table the imfiltrate, thereafter to filter the hot filtrate andtreat it to p ovgment' f fi tin aid contacting in" the presence recover the Purified ethylene P y remaining in 50111- of an organic peroxide in a proportion between about This oblfict can be achieved P ll by milling the 1 and about 10% by weight, based on the Weight of said filtrate to produce a precipitate of white polyethylene 3O lk li d separating a so-lid'polymer thus o. which is readily filterable by conventional methods. d d; t

The polymers ofthe present invention can be used or 9 h process f l i 8 h i id llk i treated as the polymers whose preparation is described ethylena in US. Patent 2,691,647 of Edmund Field and Morris 10. The process of claim-9 wherein said alkali metal Feller, granted October 12, 1954. 7

Having described my invention, I claim:

is sodium and said Group 4a metal is titanium.

1. In a process for the preparation of a normally solid peroxide is adialkyl Peroxide V polymer, which comprises contacting a normallygaseous, The process f claim 11 h i vsaid di lk l unbranched l-alkene capable of undergoing additionpnperoxide is 1 peroxide; 7

lymerization under polymerization reaction conditions, The process f 'claim 11 h i i di l l includingia temperature between about 10 C. and about peroxide is 2 2 1 peroxyybutane,

11. The process of claim 10 wherein said' organic and a P1"assure below 9 P- e with a P 14. The process of claim 10 wherein said organic lymerization catalyst prepared by admixing peroxide is a diacyl peroxide 7 (A) an alkali reagent selected from the class consist- 5 The process f claim 14 h i i di ing of; oxide is benzoyl peroxide. v a

alkali metal V 16. A novel composition consisting essentially of the re- 7 alkali metal hydnde action product secured by admixing at least 2 gram atomic f derivatlve, of an a l metal: weights of an alkali metal with between about 0.1 and and I about l'gram molecular weight of a titanium halide and mlxmms of Sald alkah reagents Wlth between about 1 and about 10 percent by weight, based 7 a Polyvalent metal Salt of a matal selectedcfifm on the weight of said alkali metal, of an organic peroxide. P 4a, and 8 of the Mefldeleefi 17. The novel composition of claim 16 wherein, said Perlodic Table, the lmPmvement Qf efiectmg l alkali metal is sodium and said titanium halide is titanium contacting in the presence of an organic peroxide in l tebracmoflda a pro ortion sufficient to e'fiect substantial promotion V V of th s activity of said polymerization catalyst of 7 References C1395 the file of this P r from about 0.0l'to about 20 percent by weight of V UNITED STATES PATENTS said alkali reagent, and recovering ap lymer th 2,614,101 Vmneck et a1 3 1952 7 produced- V a 2,691,647 Field et-al a Oct. 12,1954 2. The process of claim 1 whereinsaid hydrocarbon 1s 2,758,107 H fli m at Aug" 7 71956 ethyleflel a 7 2,839,518 Brebner f June 17, 1958' 3. The process ot claim 1 wherein said organicperox- 3 3 771 Ray at 1 J 13 195 9 ide is adialkvl peroxide. l t 2,868,772 Ray et'al. Jan. 13,1959 7 4.,The' process of claim 3 wherein said dialkyl peroio 3,024,227 'Nowljnet 1, M -{6,1962 ide is'di-t-butyl peroxide. 7 (S5 5. Theprocess of claim 3 whereinsaid dialkyl'perox- I FQREIGN i p a c ide is 2,2-bis(t-butyl peroxy)-butane. l 538,782 Belgmm 1955 i 6. In a process for the preparation of ,a normally solid V 1 a Bm "-f" Y'- polymer which comprises contacting a normally on: j j OTHER REFERENCES branched l-alkene under polymerization reaction conai organmMetanic Compounds, hw n ditions; including a temperature between about 10 C. Sons, 1 y Dem 29, 5 1 only needg 

1. IN A PROCESS FOR THE PREPARATION OF A NORMALLY SOLID POLYMER, WHICH COMPRISES CONTACTING A NORMALLY GASEOUS, UNBRANCHED 1-ALKENE CAPABLE OF UNDERGOING ADDITION POLYMERIZATION UNDER POLYMERIZATION REACTION CONDITIONS, INCLUDING A TEMPERATURE BETWEEN ABOUT 10*C. AND ABOUT 175*C. AND A PRESSURE BELOW 2000 P.S.I.A., WITH A POLYMERIZATION CATALYST PREPARED BY ADMIXING (A) AN ALKALI REAGENT SELECTED FROM THE CLASS CONSISTING OF: (1) ALKALI METAL (2) ALKALI METAL HYDRIDE (3) HYDROCARBON DERIVATIVE OF AN ALKALI METAL AND (4) MIXTURES OF SAID ALKALI REAGENTS, WITH (B) A POLYVALENT METAL SALT OF A METAL SELECTED FROM THE GROUPS 4A, 5A, 6A AND 8 OF THE MENDELEEFF PERIODIC TABLE, THE IMPROVEMENT OF EFFECTING SAID CONTACTING IN THE PRESENCE OF AN ORGANIC PEROXIDE IN A PROPORTION SUFFICIENT TO EFFECT SUBSTANTIAL PROMOTION OF THE ACTIVITY OF SAID POLYMERIZATION CATALYST OF FROM ABOUT 0.01 TO ABOUT 20 PERCENT BY WEIGHT OF SAID ALKALI REAGENT, AND RECOVERING A POLYMER THUS PRODUCED. 